Kumbirai Musiyiwa

and 3 more

This study investigated AMF community response to tillage and soil amendment regimes from rhizospheric soil of maize roots at 0-10 cm and 10-20 cm at Hunyani farm, Zimbabwe. Two tillage systems (conservation agriculture: CA) and conventional tillage: CT), and six soil fertility amendments [Control (C), High fertilizer (HF-120), Low fertilizer (LF-60), Manure (M), Manure + low fertilizer (MLF-60), Manure + 60 kg N ha-1 (M-60)] were laid in a split plot design with three replications. Twelve morpho-species were identified at the study site. Species richness was highest for CA+C (11.7) and CA+ M (11.7) at 10-20 cm depth. Control plots of CT had more diverse AMF species in the surface layers (Shannon-Weaver index = 2.12) compared to the subsurface soil layer (Shannon-Weaver index = 1.86). The tillage x fertility interaction showed that in CA, A. dilatata spore populations were higher in MLF-60 amended plots than all other plots, followed by LF-60 plots, while in CT systems MLF-60 promoted higher spore populations than all other treatments. All plots amended with manure plus inorganic fertilizer had lower (P<0.05) G. clavisprum spore populations than C, HF-120 and M amended plots under both CA and CT, however LF-20 promoted higher populations than in plots with a combination of manure and inorganic fertilizer in CT only. Tillage x fertility amendment x depth interactions (P<0.05) were observed on A. denticulate, A. schenkii, and C. Luteum, E. infrequens, R. clarus, and S. calospora spore populations. Medium term effects of CA+ manure, and CA + no amendments may include increasing species richness and diversity. Application of relatively large amounts of inorganic fertilizers increase populations of C. luteum populations in CA and decrease in CT. Manure reduces populations of some species e.g. C. luteum in both CA and. CT.

NILTON MASHAVAKURE

and 3 more

Earthworms are a major component of soil fauna communities with positive effects on soil chemical, biological and physical processes. A study was carried out at Chinhoyi University of Technology experimental farm, Zimbabwe, to investigate the medium-term effects of cultural practices on earthworm communities in a maize-based cropping system. Data were collected in the 2018/2019 cropping season from a six-year old experiment with tillage system (conventional, rip line seeding and basin planting), fertiliser application rate (zero, low: 35.2 kg ha−1 N + 12.2 kg ha−1 P2O5 + 6.6 kg ha−1K2O, medium: 41.5 kg ha−1 N + 14 kg ha−1 P2O5 + 7 kg ha−1 K2O, and high: 83 kg ha−1 N + 28 kg ha−1 P2O5: 14 kg ha−1 K2O.) and weeding intensity (twice, four times and clean weeding) as the main, sub- and sub-subplots, respectively. Lumbricus (34.4%) and Diplocardia (38.3%) were the dominant genera while endogeic earthworms (48.4%) dominated the community structure among other earthworm functional groups. Lumbricus abundance, total earthworm abundance, genus richness and Shannon diversity index were higher in clean weeded plots under the basin planting system relative to other treatments. Inorganic fertiliser application in the conventional tillage (CT) system reduced Eisenia abundance and genus richness. There was a positive correlation between total earthworm abundance (r = 0.34, P < 0.001) and negative correlation of Diplocardia abundance (r = -21, P < 0.05) with maize grain yield. These results suggest that in minimum tillage systems clean weeding has positive effects on earthworms while in CT, application of high doses of inorganic fertiliser is detrimental to earthworm communities.